Elevator.



B. M. WALPOLE.

ELEVATOR.

APPLICATION TILED IEB.2, 1909. 933,506, Patented Sept. 7, 1909.

/8 o o o o WITNESSES I/VVEIVTOI? I .BenjczminMwlv oole. & a? '1 r IBYWm/ow.

- ATTORNEY UNITED srnrns PATENT OFFICE.

BENJAMIN M. wearers, or rnovrmmcn, nnonn ISLAND.

Patented Sept. '7, 1909.

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933,506. Specification of Letters Patent.

Application filed February 2,1909. Serial No. 475,669.

To all whom it may concern:

Be it known that I, BENJAMIN M. VAL- roLn, citizen of the United States,residing at the city of Providence, in the county of Providence andState of Rhode Island, have invented certainnew and useful Improvementsin Elevators, of which the following is aspecification, reference beinghad therein to the accompanying drawing.

This invention relates to a duplex system of motors for operatingelectric elevators, and the like, and has for its object to provide a.pair of electric motors to rotate in opposite directions, both beingconnected thrdugh a system of difierential gearing to a driving drum,which drum may be connected by a rope orother suitable means, to thecounterweight and elevator car.

My invention consists broadly in the controlling of both of said motorsby cutting in or out electrical resistance to either one or the other ofsaid motors, whereby one is permitted to run at a greater speed than theother, the difference between said speeds operating through saiddifferential gearing is the resultant speed which acts in the directionof the greater to drive the elevator. This electrical resistance may becontrolled by a handle in the car. When said handle is in its neutral.position bot-h motors are running at the same speed and the car isstopped. When it is desired to ascend or descend the handle is movedeither to the right or to theleft thereby cutting in resistance to onemotor and proportionally cutting out resistance from the opposite motorwhereby the relative speeds are changed, the resultant being therelative speed of the elevator, the greater the difference the greaterthe speed of the elevator. A great advantage in a drive of thischaracter is that the motor armatures are not positive in their actionbut practically float, that is, one acts against the other and thedifference between these forces is the force that moves the car, thusthe action is extremely flexible, smooth and easy, completely obviatingthe jerking and vibrating motion noticeable in other types of elevatordrives. Then again, by this arrangement of cutting in the resistancestep by step, with this style of drive the car may be started graduallyand softly and almost unpercept-ibly attain the greatest speed and asgradually be brought to-a stop again without 1 the slightestdiscomfiture to the passen ers,

which is of great importance particularly in operating in high buildingswhere long distances are run at a high velocity.

A further object of the invention is to provide an automatic brakeadapted to be set by gravity, whereby when the operating handle is intheneutral position the circuit is broken to a solenoid allowing the braketo be set antomatically by grav1ty to prevent further movement of saiddrum in either direction.

Another feature of the device is that a positively operating limitswitch is attached to and controlled by the rotation of the rope drum,whereby when the elevator car approacheseither its extreme up or downposition resistance is cut in step by step until the current iscompletely cut off bringing the car to a positive stop against furthermovement.

With these and other objects in View, the invention consists of certainnovel features of construction, as will be more fully described andparticularly pointed out in the appended claims.

In the accompanying drawings: Figure 1'is a diagrammatic viewrepresenting the arrangement of the two motors which are connected tooperate through d1fferent1al gearing to a driving drum, which drum isconnected by a rope to the counterwelght and elevator car, said drum andgearing being in section. Fig. 2is a detail showing the brake forholding or locking the drum and car against movement when both motorsare running at the same speed. Fig. 3-is a diagrammatic View of thewiring, also showing a portion of the posit1vely drlven limit switchoperating mechanism.

Referring to the drawings, at 1 and 2 are the driving, motors, bothbeing mounted on a common bed plate 3. The armature, not shown, of eachof these motors is mounted on shafts 4 and 5 respectively to rotate inopposite directions, said shafts being held to run in bearings 6 and 7,and 8 and 9 respectively.

A corrugated rope drum 10 is provided with heads 11 and 12 at either endthereof and centrally located planetary pinions 13, the latter beingloosely mounted on studs 14l4 at intervals around the interior surfaceof said drum preferably about equally distant between the ends. Largegears 15 and 16 are mounted on and pinned, keyed or otherwise secured tothe armature shafts 4-and 5 respectively, the teeth of said gears beingadapted to mesh with the teeth on either side of the pinions 13-43. Anyor all of these gears may be constructed of rawhide, or fiber, ifdesired, or any other suitable material, so as to run smoothly andnoiselessly, or the drum being constructed like a tight box may receiveand retain lubricant in which the gears may run.

The face of the drum is provided with a series of grooves for thereception of the rope 17, one end of which is preferably led up over thepulleys l8 and 19 down to the counterweight 20, while the opposite end21 of said rope is connected to the underside of the counterweight, thecar 22 being connected to the upper end of said counterweight throughthe rope 23 which is led over the pulleys 24 and 25.

\Vhile the arrangement above shown of connecting the car andcounterweight is simple and practical yet I do not confine myself to anysystem ormethod of connecting to the same.

When both of the motors are running in opposite directions at the samespeed the drum 10 will not revolve, but to insure the positive stoppingof said drum I have arranged a simple brake band 26, see Fig. 2, whichengages the circular portion 27 of the drum to which brake is connectedthe lever 28 which is pivotally mounted at 29 in a suit-able bracket orsupport, a weight 30 being carried by said lever. The solenoid 31, whenenergized, is arranged to draw up i said lever, slacken the hand andrelease the drum, and when the solenoid is denergized the lever falls,tightens the band and stops the drum automatically.

In order to provide a safeguard against accident and positively shut offthe motors and stop the car before the same has gone too far in eitherdirection I have mounted a dog 32 on a screw shaft 33, said shaft being.driven positively from the drum 10 through the gears 34 and 35 wherebywhen the car approaches its extreme up position said dog will engage thelever 36 and cut in sufficient resistance, as indicated at 37, tobalance the field circuits and equalize the speed of the motors to stopthe car. Should the momentum of the car-and drum be so great as to causethe lever to be carried beyond the balancing point then the dog operatedthrough the drum would start to move in the opposite direction and theretaining spring 56 will cause the lever 36 to follow said dog andreturn to the balancing point. If, however, the car had suflicientmomentum to carry the dog to the last notch of resistance the same wouldthen engage the projection on the end of lever 38 and move the same tobreak the main circuit at 46 throu h the wire 42 simultaneously settingthe bra e 26 and positively stopping the car from further movement. Whenthe car is g01ng 1n the opposite direction a similar operation takesplace, the dog 32 first engaging the lever 39, which operates throughthe resistance 38 to affect motor No. 2 in the same manner as theoperation of lever 36 affects motor No. 1, as above described, and ifthe carcontinues to move in the same direction the dog 32 finallyengages the lever 41 which is connected to lever 38 through the bar 40,whereby the movement of this lever 41 also operates said lever 38 tobreak the main circuit at the point 46 throu h the wire 42,simultaneously setting the bra e and positively stopping the car fromgoing farther in that direction.

When it is desired to start the car the operator first grasps the handle44 of lever 44, which is insulated from segment 45, which at onceactuates the grip lever 47 throwing its contact point 48 down intoengagement with said segment 45 completing the circuit through the lever44 and wire 50 to the solenoid 51 thereby operating the knife switch 52,closing the main circuit and starting the armatures. Resistance 53 isarranged for the gradual starting of the motors. This grip lever 47referred to is normally held out of contact with the segment 45 by meansof the spring 55 by whlch arrangement if anything should happen to theoperator the circuit would automatically be broken and the mechanismbrought to a standstill.

When the contact end of the handle is carried to the right, resistanceis cut into the field of motor 1 and out of the field of motor 2,whereby the former will run faster than the latter and the resultantdilference between these speeds moves the drum to carry the car upward,and each notch given to the handle increases this difference andlikewise the speed of the car in proportion. When carried to the leftthe reverse action takes place and the car descends. Also when thecontact portion of this lever 44 is moved from its neutral position itengages either of the contact plates 5454 and completes a circuit toenergize the solenoid 31 to raise the brake bar 28 and allow the motorsto rotate the driving drum 10 and on being brought back to its neutralposition this circuit is broken by bringing lever 44 between the twocont acts 54, the solenoid dceuergized and the brake band automaticallyset as above 'described. The motors shown are shunt wound and it isfound in practice that a motor wound with a shunt field will operate theapparatus satisfactorily, but it may be found necessary when operatingunder heavy overloads to use a compound winding in order to reduce thesparking on commutator.

My invention is extremely simple and practical in its construction,effective in its operation, and by its use the elevator is under perfectcontrol of the operator, and may be started easily and smoothly andadvanced step by step until the highest speed is atany device foraccomplishing this purpose in substantially the manner shown will comewithin the spirit and scope of my invention, one practical cmbodhncnt ofwhich has been herein illustrated and described without attempting toshow all of the various forms and modifications in which my inventionmight be embodied.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. An elevator comprising two motors arranged to rotate in oppositedirections, difi'ercntial gearing driven by said motors, elevatingmechanism including a rotatable drum controlled by said gearing, thedirection of rotation of said drum being controlled by relativelyvarying the power sup plied to said motors, a brake arranged to controlsaid drum when the motors are running at uniform speed, and means forcon trolling the application of power to said motors and simultaneouslycontrolling the operation of said brake.

2. An elevator comprising two motors arranged to rotate in oppositedirections, differential gearing driven by said motors, elevatingmechanism including a rotatable drum controlled by said gearing, thedirection of rotation of said drum being controlled by relativelyvarying the power supplied to said motors, a brake arranged to controlsaid drum, an electro magnetic device controlling said brake and incircuit with said motors, and means for controlling the application ofpower to said motors and simultaneously controlling said magneticdevice.

3. An elevator comprising two motors arranged to rotate in oppositedirections, differential gearing driven by said motors, elevatingmechanism including a rotatable drum controlled by said gearing, thedirection of rotation of said elevating mechanism being controlled byrelatively varying the power supplied to said motors, said meansincluding a resistance in circuit with the fields of both motors andmeans for simul taneously increasing the resistance in the field circuitof one motor and correspondingly reducing the resistance in the fieldcircuit of-the other motor, a brake arranged to control said drum, anelectro-magnetic device controlling said brake, and means operatedsimultaneously with the resistance controlling means to energize. saidmagnetic device.

4. The combination with two motors arranged to rotate in oppositedirections. dittcrcntial gearing driven by said motors, elevatingmechanism controlled by said gearing, and a car operated by saidmechanism at means for automatically throwing a resistance. into thecircuit of either motor as the car approaches the limit of its movement.

I). The combination with two motors ar ranged to rotate in oppositedirections, ditt'erential gearing driven by said motors, clevatingmechanism controlled by said gearing, and a car operated by saidmechanism, of means for automatimilly throwing a resistance into thecircuit of either motor as the car approaches the limit of its movement,and means whereby continued n'iovement of the car will subsequentlybreak said circuit.

(3. The combination with two motors arranged to rotate in oppositedirections, dit' terential gearing driven by said motors, elevatingmechanism controlled by said gearing, and a car operated by saidmechanism, a resistance, a contact arm, a circuit breaker or limitswitch, and means for operating said contact arm to cut in saidresistance and to subsequently operate said circuit breaker or limitswitch to open the circuit.

7. The combination with two motors arranged to rotate in oppositedirections, differential gearing driven by said motors, elevatingmechanism controlled by said gearing, and a car operated by saidmechanism, of resistance, contact arms cooperating with said resistance,and means conforming to the movement of the car to operate either ofsaid arms to cut in said resistance.

8. The combination with two motors ar ranged to rotate in oppositedirections, differential gearing driven by said motors, ele vatingmechanism controlled by said gearing, and a car operated by saidmechanism, of resistance, contact arms cooperating with said resistance,means conforming to the movement of the car to operate either of saidarms to cut in said resistance, and means whereby continued. movement ofthe car will break the circuit.

9. An elevator comprising two motors arranged to rotate in oppositedirections, an elevating drum, ditterential gearing connecting said drumand motors, a brake collar on one end of said drum, a braking devicecooperating therewith, means for controlling the application of power tosaid motors and simultaneously controlling said braking device, andmeans actuated by the other end of the drum for reducing the speed ofrotation thereof at predetermined periods.

10. An elevator comprising two motors arranged to rotate in oppositedirections, an elevating drmn, diflerential gearing connecting said drumand motors, a brake collar on ing, a car operated by said mechanism, a

lever in said car for controlling the field and armature circuit, meanson said lever whereby the main circuit is completed before said lever ismoved, and means for automatically throwing a resistance into-thecircuit of either motor as the car approaches the limit of its movement.

In testimony whereof I affix my signature in presence of two witnesses.

BENJAMIN M. WALPOLE.

Witnesses:

HOWARD E. BARLOW, E. I. OGDEN.

